Page 4 - Volume 15 Number 10

CORRESPONDENCE
A Missed Opportunity
Tom Clements’ article in the July issue titled, “Practice Demonstration of VMCA” was a missed opportunity to clarify that just because a manufacturer has an Aircraft Flight Manual (AFM) “approved procedure” doesn’t mean it is always a good idea to follow same.
The procedure as presented in the article
and AFM is in conflict with both the AFM’s
information on the purpose of VSSE and
various communiqués issued over the
years about the hazards of single engine
operations and training related to single
engine stall-spin accidents in multi-engine
airplanes. As stated by the AFM regarding
VSSE: “Intentional failing of one engine
below this speed is not recommended.”
Note that this statement does not excuse
purposefully rendered (or simulated) inoperative for training. Whether due to loss of rudder effectiveness OR wing stall, SE operations below VSSE has the potential for drastic rolling/wing drop components from which recovery could be impossible.
There is NEVER a pilot training nor real-life requirement (beyond certification flight testing) to duplicate nor “check” what any multi-engine aircraft’s actual AFM indicated VMCA (Red Radial Line) might be.
Instead, the sole purpose of VMC pilot training and demonstration should be to reinforce the pilot’s need to maintain directional control (HDG) in split power conditions, at all costs, primarily with use of rudder AND if/when adequate control cannot be maintained or is in doubt (for any reason known or unknown), reduction of power on all engines (toward idle) must be the first response to loss of HDG control (i.e., decrease or eliminate asymmetric thrust causing directional control problem) while then increasing airspeed (for added rudder effectiveness) with maximum application of all available rudder and flight control inputs required.
Pilot training of VMC is ONLY about control, not about performance to be obtained (max climb or min descent) during SE operations. VMC inflight training is NEVER about the Red Radial Line, it is only about maintaining directional control and the potential for loss of control in asymmetric power situations, especially with loss of airspeed. The loss of any airspeed results in reduced rudder effectiveness AND nearing loss of control potential when near and below VSSE, due to loss of margins for adequate rudder control and/or stall-spin prevention.
VMC training is about avoiding any SE operations with asymmetric thrust below VSSE and/or if control cannot be maintained at ANY SPEED, in order to avoid SE loss of control and SE stall-spin situations all together, reduce asymmetric thrust and AOA to increase control effectiveness until above VSSE. In reality, NO intentional or unintentional single engine operations should be conducted below VSSE.
If more pilots were taught the emphasis of reducing power when below VYSE and accelerating toward VSSE when directional control is in doubt (well before published VMC), there could be far fewer SE rollover accidents (i.e., right side up even off airport is better than an upside-down crash anywhere). Review King Air loss of directional control accidents (ADS & ICT, etc.) and know that an early reduction in asymmetric thrust (no matter the reasons encountered) could have completely changed the outcomes.
Please rethink “Loss of Directional Control” inflight single engine training and all SE operations ...
Sincerely, Kevin P. Hynes
2 • KING AIR MAGAZINE
OCTOBER 2021
ASK THE EXPERT
Have you ever seen this procedure described? I hope your answer is “Yes,” since it is the title of a procedure presented in the Pilot’s Operating Handbook (POH).
Practice Demonstration of VMCA
1. Landing Gear........................................................................... UP
2. Flaps........................................................................................ UP
3. Airspeed ........................................... ABOVE 104 KNOTS (VSSE)
4. Prop Levers ................................................................ HIGH RPM
5. Power Lever (simulated inoperative engine) ........................ IDLE
6. Power Lever (other engine).................. MAXIMUM ALLOWABLE
7. Airspeed – Reduce approximately 1 knot per second until either
by Tom Clements
Use rudder to maintain directional control (heading) and aileron to maintain 5° bank towards the operative engine (lateral attitude). At the first sign of either VMCA or stall warning (which may be evidenced by: inability to maintain heading or lateral attitude, aerodynamic stall buffet, or stall warning horn sound) immediately initiate recovery: reduce power to idle on the operative engine and immediately lower the nose to regain VSSE.
18 • KING AIR MAGAZINE JULY 2021
JULY 2021
KING AIR MAGAZINE • 19
Quiz time: In what POH section will you find it? Section 3, Emergency Procedure? Section 3A, Abnormal Procedures? Or Section 4, Normal Procedures?
I will wager that less than half of our readers answered correctly, with “Section 4, Normal Procedures.” But indeed that’s where it is found, right after the procedure titled “Simulating One-Engine-Inoperative (Zero Thrust).” Since multi-engine training is a normal procedure that can be done, and often is done, in King Airs this makes both of these procedures quite normal. Here is the entire written procedure found in the B200 model’s POH:
PRACTICE DEMONSTRATION OF VMCA
VMCA demonstration may be required for multi-engine pilot certification. The following procedure shall be used at a safe altitude of at least 5,000 feet above ground in clear air only.
WARNING
IN-FLIGHT ENGINE CUTS BELOW VSSE SPEED OF 104 KNOTS ARE PROHIBITED.
VMCA or stall warning is obtained.
NOTE